The evidence used by courts and tribunals to establish capacity: A study comparing three different types of capacity

Sam Boyle1

1 TC Beirne School of Law, University of Queensland, St Lucia, QLD 4072,

In order to investigate how courts and tribunals determine capacity, a case study was done in Queensland. The study compared capacity decisions by courts and tribunals for three types of capacity: personal and/or financial capacity (decided in the guardianship/administration jurisdiction), testamentary capacity, and capacity to conduct legal proceedings. The study examined the types of evidence used in those decisions, how that evidence was used, and how this differed between the capacity types. The results showed two very clear patterns: firstly, adults in the guardianship/administration jurisdiction are far more likely to be found to lack capacity, and secondly, there is far greater use of medical evidence by the tribunal deciding personal/financial capacity than either of the two other types of capacity. This was manifested both in the rate of agreement between the tribunal and medical experts who provided evidence, and in the weight given to that evidence, especially in comparison to other available sources of evidence, such as that gathered from the adults themselves. These results are illuminating, and add to the empirical understanding of how capacity is determined in a legal setting. Also, the dramatic weight given to medical evidence in the guardianship/administration jurisdiction revealed in this study raises five possible concerns, which will be explored in some depth. These concerns include questions over whether the relative weight given to medical evidence in that jurisdiction matches the probative value of this evidence; it also includes concerns over the respective roles of doctor and patient, and the potential for patient disempowerment in the process of deciding capacity.


Sam is a researcher who is looking at the question of capacity, particularly in the case of mental illness. He is conducting a PhD on the question of how capacity should be determined in the case of Anorexia Nervosa. This involves consideration of the bioethical issues surrounding capacity assessment, and an empirical study of how capacity is determined in a legal setting. Sam also lectures in and has published in the areas environmental and property law.